If you dont play with the perfect number of players neutrals come into play. You never actually get a apy card(3000 pieces), its just there to replicate the randomness/luck of cards in classic risk. Sometimes it takes 3 cards sometimes 5. This also removes the need to only offer 9 for a set 10 can be used for a set.

It's a template for 6 players. To change I'd recomend changing the number of territories distributed before introducing neutrals. As neutrals are not a part of risk - but differing amounts of players means different amounts of starting spots in a risk game.